- SQL: database operations
- XLST: tree transformations
- Regex: regular expressions
- EBNF: syntax and grammar description
- Prolog: backtracking rule engine
- AMPL: as a modelling language for mathematical optimisation problems
- HTML: seen as a document description language
- Meaning of data/problem statically defined.
- Represenatation/solution process is external.
- Represenatation/solution process is exchangeable.
- No internal control over external solution process.